Biosphere

THE ENVIRONMENT of the Earth can be broadly divided into four major systems: the atmosphere, hydrosphere, lithosphere, and biosphere. Russian scientist Vladimir Vernadsky coined the term biosphere in 1929. The term refers to the life zone of Earth that includes the air, land, and water occupied by all organisms including humans. This life zone distinguishes our planet from all others in the solar system.

The biosphere fulfills several important functions and processes to sustain life. These processes include the ways that solar energy and PRECIPITATION control biotic productivity, the interactions among various life forms, and how life forms have spread over the Earth’s surface and adapted to various habitats. These processes are not limited to only the biosphere, but are the result of complex interactions between all the major systems (the atmosphere, hydrosphere, and lithosphere).

For example, the biosphere is both a source and sink for several important atmospheric trace gases and environmental pollutants (methane and nitrous oxide, for example). It is an essential factor in determining the budget, abundance, and distribution of trace gases in the atmosphere. Different types of forests create different atmospheric conditions that influence climate and ecosystem functioning. Chemical reactions critical to both life and atmospheric processes include photosynthesis and respiration.

Water is essential for all living organisms, and the biosphere plays a crucial role in the transportation, transformation, and redistribution of water on local and regional scales. In terrestrial ecosystems, vegetation plays the primary role in transferring water from the soil to the atmosphere. The biota exerts measurable effects on water quality through recycling of nutrients and absorption of air and water pollutants. Biospheric processes are also evident in the lithosphere. Root growth and the generation of organic acids aid in chemical and mechanical weathering of soils and geologic materials. Decomposition of organic material add nutrients to the soil.